Computing machine



July 21, A. Q SEYMOUR 2,048,568

COMPUTING MACHINE Filed Jan. '7, 1935 5 Sheets-Sheet l S l E a, Bil A61) h INVENTOR I I ,r

ATTORNEY July 21, 1936. Q SEYMOUR 2,048,568

COMPUTING MACHINE Filed Jan. 7, 1935 3 Sheets-Sheet 2 I %VE TOR W July 21, 1936. c SEYMOUR 2,048,568

COMPUTING MACH INE Filed Jan. 7, 1935 3 Sheets-Sheet 3 ATTORNEY Patented July 21, 1936 UNITED STATES PATENT OFFICE COMPUTING MACHINE ration of Delaware Application January 3 Claims.

My invention relates to calculating or computing machines, and especially to combined typewriting and computing machines having algebraic totalizers and clearance proof mechanism.

One of the principal objects of my invention, generally stated, is to provide an improved and highly efllcient clearance proof mechanism for algebraic totalizers which will test for both positive and negative clearance.

Another object of my invention is to provide an improved positive and negative clearance proof mechanism which can be readily incorporated in an algebraic totaiizer without materially modifying said totalizer.

A further object of my invention is to provide a positive and negative clearance proof mechanlsm which operates independently of the shutter control in the totaiizer.

More specifically, it is an object of my invention to provide a positive and negative clearance proof mechanism which comprises a feeler for each of the positive and negative sets of numeral dials in the totalizer, and a resetting arm for each of said feelers and cooperating independently therewith.

A still further object of my invention is to provide a separate and independent train of operating connections between each of. the two independent resetting arms and its feeler, and in which the parts of each train are maintained constantly in operative connection and are automatically controlled to automatically and selectively control the movement of the resetting arms into and out of Operative position.

To the above and other ends which will hereinafter appear my invention consists in the features of construction, arrangements of parts and combinations of devices set forth in the following description and particularly pointed out in the appended claims.

In the drawings wherein like reference characters designate corresponding parts in the different views:

Fig. 1 is a vertical fore and aft sectional view 45 through an algebraic cross totalizer constructed in accordance with my invention and showing the clearance proof mechanism set for a negative clearance;

Fig. 2 is a fragmentary fore and aft vertical K sectional view of part of the mechanism illustrated in Fig. 1 and showing the clearance proof mechanism set for positive clearance;

Fig. 3 is a fragmentary vertical sectional view taken along the line 3-4 of Fig. l and looking 55 in the direction of the arrows at said line;

I, 1935, Serial No. 581

Fig. 4 is a horizontal sectional view of the totalizer taken along the line 4-4 of Fig. 1 and looking in the direction of the arrows at said line;

Fig. 5 is a detail perespective view of the connecting disc for the positive clearance proof 5 mechanism;

Fig. 6 is a detail perspective view of the special carrying wheel for the fugitive 1 mechanism;

Fig. 7 is a detail perspective view of one of the regular carrying wheels of the totalizer; 10

Fig. 8 is a detail perspective view of the feeler comb for the positive clearance proof mechanism; and

Fig. 9 is a fragmentary perspective view of an algebraic totalizer embodying my invention, showing some of the other operating parts of a. combined typewriting and computing machine associated therewith.

In all of the views the parts are shown on an enlarged scale.

My invention may be regarded, in some respects as an improvement on the general types of clearance proof mechanism shown and described in Patent No. 1,490,129 to Arthur F. Poole, No. 1,490,989 to Carl A. Sieweck and No. 1,491,898 to Robert G. C. Boa. In the Poole patent clearance testing mechanism is provided which is adapted to show clear whether the reading is from positive numeral dials or from negative dials; and the mechanism comprises a single feeler which coacts with the intermediate gears of the totaiizer and may beshifted to either of two positions for positive or negative clearance. The Boa patent discloses mechanism for the same purpose which comprises a sort of double feeler device pivoted to swing about an axis through the central portion thereof and adapted to be swung into engagement with one gear of each denominational gear train in order to test for positive zero, and adapted to be swung inthe opposite direction into engagement with another gear of each denominational train in order to test for negative zero. According to the Sieweck patent which attains the same general ends, two different feelers are provided, one of which 00- operates with one wheel in each denominational train to test for positive zero, and the other of which cooperates with another wheel of the same train to test for negative zero.

In all of the above constructions one resetting arm coacts with the feeler or feelers used. Furthermore, since only one resetting arm is employed, it is necessary to provide a selecting mechanism which either will shift the feeler or the connections to the resetting arm when the totaliaer changes from a positive to a negative state. In each instance this is rather a delicate and complex mechanism which coacts with the lever employed to shift the shutters used in conjunction with the positive and negative numeral dials.

According to my present invention I provide iii an algebraic totalizer having a train of gearing for each denomination a mechanism of the same general type referred to above, which comprises a resetting or control arm coacting with a feeler which in turn cooperates with one wheel of each denominational train to test for positive clearance; and a second resetting arm coacting with a second feeler which is adapted to cooperate with another wheel in each train to test for negative clearance. Since two resetting arms are employed I am enabled to eliminate the use of the above described selecting mechanism cooperating with the shutter control lever, and thereby provide a simple and highly effective positive and negative clearance testing device in which there is a separate and constantly maintained train of connections between each resetting arm and its feeler, as will hereinafter more clearly appear.

The drawings in the present case represent the invention in the form in which it is embodied in combined typewriting and computing machines, such as are known as Remington accounting and bookkeeping machines. The construction and operation of such machines, not including the clearance proof mechanism, is explained in Patent No. 1,270,471 to J. C. Wahl, to which reference is made for a disclosure of any mechanism which the drawings in the present instance do not show and which Remington accounting machines in-- clude. or any mechanism which is particularly referred to but not fully illustrated herein. It should be understood, however, that the invention is not restrlcted'to its use in such machines but may be applied to different forms of calculating or computing machines of this same general type wherever found available.

The Remington accounting machine is so well known and the calculating mechanism of it so well described in the Wahl patent above referred to, that I have illustrated only those parts of the machine which immediately cooperate with the devices of the present invention.

In many of the previous algebraic totalizers, as for example that shown in Patent No. 1,753,711 to L. S. McCorn, dated April 8, 1930, there are two sets of numeral dials. In such totalizers the upper set of numeral dials is generally used to show positive totals and the lower set is used to show negative totals. However, in the totalizer in wh ch my invention has been embodied, this construction has been reversed and the upper set of dials is used for registering negative totals and the lower set of dials is used for positive totals. The reason for this change resides in the fact that in practice it was found that the lower set of d als is more readily visible by the operator. Therefore, since in most forms of work positive totals occur more frequently than negative totals, it has been found advantageous to reverse the former construction and use the lower set of numeral dials for the registering of positive totals.

I shall first describe the general construction of the totalizer, and will follow this with a description of the positive and negative clearance proof mechanism made in accordance with" my invention.

The Remington accounting machine includes a Remington typewriter having mounted on its frame the Wahl calculating mechanism, the latter including among its several parts the usual cross truck III, as shown in Figs. 1 and 9. Secured to thecross truck II by a latch lever H is the cross totalizer which is designated as a whole by the reference numeral I2. The framing of the totalizer itself comprises a right-hand side plate If, a left-hand side plate II and various connecting rods and bars I! secured at their ends by any suitable means to these side plates and extending transversely between them. Top and front cover plates l3- and II respectively are secured to some of the cross rods I5 by means of screws l5 as shown in Figs. 1 and 9.

As is well known, the ordinary Remington'or Wahl totalizer is operated one denomination at a time. The wheels in each denomination comprise a carrying gear or wheel ii mounted on a fixed pivot rod an intermediate or idler gear i8 mounted on a fixed pivot rod I9, and a pinion 20 rigid with a dial 2| on which the amounts are read, both said pinion and said dial being mounted on a fixed pivot rod 22. The transfer mechanism is of the so-called "Geneva type and it includes the usual stop works or transfer gears 22 each mounted on a lever 24 having a lower projecting end 24. The levers 24 are of two kinds pivoted on frame rods 25 and 26 respectively, and at their upper ends they all normally rest agaimt stop screws 2'! and cooperate with a universal locking bar 28. In operating the totalizer one denomination at a time the register wheels and transfer mechanism are controlled by an actuator which comprises a master wheel 29 (Fig. 1) adapted to be successively engaged by the carrying wheels It as the cross totalizer receives a step-by-step advance movement with the main carriage; and at such time a master dog 30 registers successively with the lower projecting ends 24' of the transfer levers 24. The fragmentary illustration of these two parts 29 and II in Fig. 1 is intended as a conventional representation thereof as employed in the Remington or Wahl actuator.

As stated above, in some totalizers of this same general type it has been customary to have the upper set of dials, in the present instance the dials 2|, register the positive numbers. However, in the present embodiment of my invention the dials 2| are used to register the negative numbers, and there is provided an additional set'of pinions 3| having dials 2'! for the registering of the positive numbers. The pinions 2| and the dials 22 are carried on a fixed pivot rod 32 and said pinions are arranged to mesh with the idler gears I8. Each of the positive or lower dials 22 contains the numerals 0" to 9" arranged on the periphery thereof in counter-clockwise order. The numerals on the dials 2| are arranged in reverse order to those on the dials 22 and are so set that when a "0" shows through a lower sight opening 34 a 9" will show through an upper sight opening 24' or vice versa, both of said sight openings being provided in the front cover plate I4.

For the purpose of displaying the proper total, positive or negative, as the case may be, and to conceal from view the other totals, there are provided two shutters 25 and 36 for the dials l2 and 2| respectively. These shutters are in the form of bails having arms pivoted on the fixed pivot rods of the dials they are to cover. On the pivot rod IQ of the idler gear I! there is pivoted a lever 31 (Fig. 2) having an arm 38 which projects through a slot 30' (Fig. 9) in the front cover plate l4 and serves as a handle for turning said lever. This lever is provided with two pins II and 40 which are located forward of the pivot rod I. and one on either side of the handle II. The pin 39 projects into a slot 4| provided in an arm 42 on the shutter 38, while'the pin 40 projects into a slot 43 provided in an arm 44 on the shutter 15. The arrangement of the above described shutters l4 and 36 and lever 21 cooperating therewith is such that when the handle ll is in its lower position, as shown in Fig. 2, the shutter 2| will be out of registry with the sight opening 34 so that a positive total may be observed, whereas the shutter 36 will register with the opening 34. when, however, the arm 38 is moved to its upper position, the shutters l5 and 34 will move to the positions shown in Fig. l where the shutter I4 is moved away from the sight opening 34", and allow a negative total to be observed, while the shutter 35 extends across the opening 34.

At its inner end the lever I1 is formed with a series of gear teeth 45 which mesh with a series of gear teeth 46 on an operating-wheel or disc which is designated as a whole by the reference numeral 41, and is shown detached and in perspective in Fig. 6. This disc or wheel is pivoted on the pivot rod l1 of the carrier gears I! just to the right of the carrier gear of lowest order.

The wheel 41 has for its purpose the carrying to the gear 18 of lowest order, the so-called "fugitive l", which must be subtracted or added every time an alegbraic totalizer changes from a positive to a negative total, or viceversa. The construction of this wheel is very similar to that of a carrying gear It, for like said gear 1| it is made, in the present instance, in three planes or strata. The right-hand strata of the carrying gear It includes the usual 30 teeth, whereas in the corresponding strata of the wheel 41 there are the teeth 46 which mesh with those provided on the lever I1. For the purpose of comparison the two wheels 41 and I6 are shown in perspectivc in Figs. 4 and 1 alongside one another so that their similarities may be noted. In the middle plane of the wheel it there are three transfer teeth 48 but on the wheel 41 there is only one transfer tooth which is designated as 48. The left-hand plane of both wheels consists of a lock ng disc having a circular perimeter designated as 4! in the wheel l6 and as 49 in the wheel 41. The perimeter 4! is broken by notches 50, one for each transfer tooth 48, and l kewise the perimeter 49 is provided with a notch 50' for its transfer tooth. It will be noted that the transfer tooth 40- is integral with a flange 5| in the plane of the teeth 46, and by such a construction is given greater strength and rigidity. A lever 24 and transfer gear 23 are provided to operatively connect this wheel 41 with carrying gear 16 of lowest denominational order in much the same way that one of said gears II is operatively connected through transfer mechanism with the gear ii of the next higher order,

as is well known in totalizers of this kind. It will be perceived that whenever the handle 24 is moved upward from the position shown in Fig. 2, the tooth 48 of the wheel 41 is turned in a counter-clockwise direction a distance sufiicient to turn theusual star wheel 52 of the associated transfer'or Geneva" gear 28 the distance of one tooth, with the result that the companion gear l6, and in fact the whole gear train of lowest order will move one tooth in subtracting direction. When said handle is then moved downward, the

wheels turn in an adding direction back to normal position.

In order to limit the extent of the rocking motion of the wheel 41 in both directions, a pin or stud 82 (see Figs. land 2) is riveted in the side plate I! and projects into the plane of the wheel 41. The right-hand stratum of said wheel is cutaway so as to leave two lugs 54 and BI in such position that one of them engages the stud I! to arrest the wheel when moving in one direction, and the other engages the stud when said wheel is moving in the other direction.

In order to retain the parts in'one or the other of their two positions two notches l4 and I1 are provided in the periphery of the wheel 41 to receive and cooperate properly with a V-shaped nose It (see Figs. 1 and 2) on a detent lever SI which is pivoted on the rod 25 and drawn downward by a spring 40, similar to those which act on the levers 24. The detent lever 89 is made similar to those usually employed in the Wahl totalizer to control the register wheel of lowest order. Thislever is riveted, as at I, to the side of ,a longer lever 42, which is somewhat like the levers 24 except that it does not carry a gear 23, I

but at its free end cooperates like the levers 24 with a stop screw 21 and the universal locking bar 22. The spring I. which tends to pull the V-shaped nose 58 into one of the notches 50 or B1 is attached at one end in an opening 63 in the lever 42 and at its other end to a rod 44 which also constitutes an anchorage for the springs that are used in conjunction with the levers 24.- The foregoing construction is such that when the handle I! is operated the motion of the wheel 41 cams the nose 58 out against the force of the spring 60 until the turning of the wheel is nearly completed when said nose is drawn downward by the spring Bl into the notch 51 to complete the motion of the parts to. and retain them, in shifted position.

Having thus described the construction of the algebraic totalizer in which my invention may be embodied, I shall now describe the positive and negative clearance proof mechanism used in combination therewith. In the present instance the upper set of numeral dials is used exclusively for the registering of negative numbers and therefore, the mechanism cooperating with the nu-- meral dials of the upper set will show or indicate a negative proof of clearance. This mechanism comprises a feeler comb II pivoted at 66 in the side plates of the cross totalizer, and when the dials I! register zero said ,feeler engages a short tooth 81 provided on each of the numeral dial gears 20. This feeler comb 46 is constructed and operated substantially like the comb 15 shown in Fig. 8, and a more detailed showing thereof than that included herein is therefore deemed unnecessary. Extending rearward from the pivot 86 of the feeler comb i5 is an arm 88 having a rounded end portion 42. A second arm 4! is pivoted on the pivot rod 24 and extends forward therefrom being bifurcated at its forward end to receive the rounded end portion II and provide an operative connection between the arms 68 and 4!. The arm 0! is drawn upward by a spring 1| which is attached at one end to said arm and at its other end to a cross bar 1| fixed in the side plates of the totalizer. This upward movement of the arm 89 is transmitted to the arm 68 and tends to turn the feeler comb in a counterclockwise direction (Fig. 1) to press said feeler against the teeth of all of the pinions 20.. The arm II is one arm of a bell crank, the other arm I2 of which constitutes a finger, resetting arm or control member which projects upward through an opening I3 provided in the top cover plate I3"- of the totalizer. This finger cooperates with other mechanism mounted on the stationary frame work of the machine, which mechanism may be of any suitable type, as for example, a star proof of clearance mechanism of the sort shown in the patent of F. A. Hart No. 1,737,586 dated Dec. 3, 1929. One form of this cooperating mechanism will be hereinafter more fully described.

Referring now to the dials 32 for registering positive numbers it will be recalled that said dials occupy a new position in the lower portion of the totalizer. In order to take care of the proof of clearance of positive numbers, it has been found desirable to provide a second and independent feeler cooperating with this lower or positive set of numeral dials. This positive proof of clearance mechanism will now be described.

Arranged below the dials 32 and in a position to cooperate with the teeth of all of the pinions 3I is a second feeler comb I5. This feeler comb 15 is shown in perspective in Fig. 8 and comprises the usual axis or shaft I8 provided at its ends with lugs II and I8 by which it is pivoted into the side plates of the totalizer. A web or supporting plate I8 extends radially forward from the shaft I6 and is provided with the usual ribs These ribs correspond in number to the number of dials in the totalizer and are so positioned in said totalizer as to be capable of cooperating with the teeth of all of the pinions 3|. One tooth 8| of each of the pinions 3I is made short, and each tooth 8| registers and cooperates with an associated rib 88 on the comb I when all of the dials 32 stand at zero, as shown in Fig. 2. An arm 82 is fastened to the right-hand end of the comb I5 (left-hand end as shown in Fig. 8) and projects rearward therefrom. A rounded portion 83 is provided at the end of the arm 82 which is received in a notch or indenture 84 provided in the periphery and at the left-hand side of a connecting disc 85, as the parts are shown in Fig. 2. This disc 85, which may be provided with a hubbed bearing 85* is mounted on the pivot rod II to the right of the wheel 41 and separated therefrom by a spacing sleeve 85 as shown in Fig. 4. The hubbed bearing 85 constitutes a means for holding the disc away from the side plate I3. A notch 86 similar to the notch 84 is provided in the disc 85 substantially diametrically opposit'e the notch 84. Received in the notch 86 is a rounded engaging portion 81 provided on the forward end of an arm 88 which is pivoted on the pivot rod 25. A spring 88 attached at one end to the arm 88 and at its other end to the connecting rod II tends to move the arm 88 upward about the pivot 26. Such movement of the arm 88 turns the disc 85 in a counterclockwise direction, as the parts are shown in Figs. 1 and 2, which results in an upward movement of the ribs 88 of the feeler comb tending to press said ribs against the teeth of all-the pinions 3|. The arm 88 is one arm of a bell crank, the other arm 88 of which constitutes a second finger, resetting arm or control member which projects upward through the opening I3 in the top cover plate I3 of the totalizer. This finger or resetting arm 88 is similar in construction and function to the resetting arm I2 and is arranged adjacent thereto but differs from said arm I2 in that it controls the lock for positive clearance, while the arm 12 is used for negative clearance.

It is to be understood that each of the two fingers or resetting arms I2 and 88 may oscillate between two positions, one in which the finger occupies a. rearward effective or operative position and the other a forward ineffective position. These two positions are controlled by the associated feeler combs which in turn cooperate with and are controlled by the teeth of the dial pinions; the pinions 28 controlling the comb 85 and resetting arm I2 and the pinions 3| controlling the comb I5 and resetting arm 88. When either feeler comb engages all of the short teeth provided on the associated pinions at the zero position of the dials, the associated finger or resetting arm will occupy its rearward, effective or clear" position. When either feeler engages any of the other teeth on the associated pinions, the companion resetting arm orflnger will occupy its other or ineffective position, which may be termed the not clear position. In Fig. 1 the arm I2 for the upper or negative set of dials is in the clear position while the arm 88 is in the not clear" position. Fig. 2 shows the reverse of this with the arm 88 in clear position and the arm I2 in not clear" position.

Referring more particularly to Fig. 9 it will be seen that the mechanism cooperating with either of the fingers I2 or 88 includes a frame plate or bracket 9i secured to the ends of the usual computing mechanism actuator frame casting (not shown). A lever 82 is pivoted to this plate at 83 and is given a normal tendency to move down at its left-hand end or turn in a counter-clockwise direction about the pivot 83 by a spring 84. At the outer or left-hand end the lever 82 has an ear 85 bent oil? laterally therefrom and having in it a notch 88 which receives an edge of the bracket 8| to guide said lever in its up and down movements. Secured to and off-set from the lever 82 by means of the connecting studs 81 is a cam bar 88 having at its left-hand end an inclined edge 98. This cam bar 88 is so situated that when either of the fingers I2 or 88 is in its rear or clear" position, and when the cross totalizer Jumps to the right after the completion of an entry which clears the totalizer, the finger in clear position will strike the incline 88 and raise the lever to the position shown in Fig. 9.

By raising the member 82, 88 in the manner described a release of the star printing key from its lock in the usual manner or an automatic imprint of the clearance proof star will be effected as will hereinafter more clearly appear. If on the other hand the totalizer is not clear" the fingers I2 and 88 will be in the forward ineffective position and will pass inifront of the bar 88 on the return of the totalizer and leave the member 82, 88 in its normally depressed position, thus conditioning the machine to lock the star key as will presently appear.

A lever I88 is pivoted at IN to the actuator frame casting and at its right-hand end is bifurcated or forked at I82 to embrace the ear 85 on the lever 82 so that said lever I88 may be rocked up and down by the lever 82. Said lever I88 has a depending branch or arm I83 terminating in a tongue or locking finger I 84 which passes through a suitable guide hole I85 in the usual frame plate I88. When the lever I88 is in its elevated or clear position, the end of the finger I84 occupies a position just inside the plate I and does not project leftward therefrom. However, when said lever I00 drops to its lower or "not clear position, the finger llll projects through the opening ill! a short distance leftward from said plate I06.

Lying flat against the outer side of the plate I and pivoted thereto at III! is a bell crank I", having a rearwardly extending arm I09 and an upwardly extending arm II. The arm ID!" of the bell crank is connected by a link III with the key lever 2 having a key H3 which when depressed effects the printing in the usual man ner through the sub-lever Il connected with said key lever and the type bar that prints the star of the clearance proof signal or symbol, which in the present instance is a star, as shown on the key 3. The upwardly extending arm 0 of the bell crank I08 normally occupies a position immediately in front of or adjacent the opening I05 in the plate I06, but is adapted to swing rearward over said opening when the key 3 is depressed. If, however, the levers 92 and III! are in their depresed positions, the locking finger M will be projecting into the path of the arm ill to lock said arm and the associated key 3 against operation. During that step of the carriage which follows the writing of the last digit of a balance, the cross truck I0 makes its jump to the right as usual. If the writing of the balance has brought the dials of the totalizer to either positive or negative zero, either of the fingers 9|! or I2 will cam up the lever 92 withdrawing the finger II to ineffective position thus unlocking the star key so that the star can be written in the next letter space position. However, if the operator has not copied the total correctly, the lever 92 will not be raised and the star key will remain locked. Such a condition indicates to the operator that some error has been made.

In the light of the foregoing description it will be apparent that by my present invention I have provided a highly eflicient and improved clearance.proof mechanism for an algebraic totalizer in which there is a separate and independent train of connections between each set of dials and the associated resetting arm; in which the elements of each train are positively connected and that such connection is constantly maintained and operated entirely independently of the elements of the other train; wherein the mechanism is comparatively simple and may be readily incorporated in existing totalizer constructions without modifying, or materially modifying the existing structural features thereof; and wherein the control of the resetting fingers 90 and 12 for positive and negative clearance respectively is automatically effected without the actuation of a manually controlled part connected therewith. It also will be observed that the algebraic totalizer is provided with a lower set of numeral dials for showing positive amounts and a second or upper set for showing negative amounts. It is to be understood that this mechanism functions in conjunction with means for preventing the printing of a clear signal when the totalizer is not clear.

It is also to be understood that according to my present invention, the provision of two resetting arms eliminates the use of any selecting mechanism cooperating with the shutter control lever, and hence provides a much simpler device capable of attaining all the ends specified.

Various changes may be made in the construction, and certain features thereof may be employed without others, without departing from my invention as it is defined in the accompanying claims.

What I claim as new and desire to secure by Letters Patent is:

1. In a calculating machine, the combination of a group of register wheels including an upper set of numeral dials for indicating negative totals and a lower set of numeral dials for indicating positive totals, a set of gears for each set of said dials, and proof of clearance mechanism comprising a feeler arranged to act on said gears for the positive dials, a second feeler arranged to act on said gears for the negative dials, and a pair of resetting arms, one of said resetting arms cooperating with said first mentioned feeler n to control for positive clearance, and the other of said arms cooperating with said last mentioned feeler to control for negative clearance.

2. The combination with an algebraic totalizer having a train of gearing for each denomination, of clearance proof mechanism including a positive clearance proof device comprising a resetting arm and a feeler controlling said arm and cooperative with one wheel of each denominational train, and a negative clearance proof device comprising a second resetting arm and a second ieeler controlling said arm and cooperative with another wheel of each denominational train.

3. The combination with an algebraic totalizer having a train of gearing for each denomination, of clearance proof mechanism including a positive clearance proof device and a negative clearance proof device; said positive device comprising a feeler cooperative with and controlled by one wheel of each train, a controlling arm, and a connecting device mounted concentrically with another wheel in one of said trains and efiecting a positive and constantly maintained connection between said feeler and said arm; and said negative device comprising a second feeler cooperative with a third wheel in each train and positively and constantly connected with a second controlling arm.

ARTHUR C. SEYMOUR. 

